Unless you are an intelligent and strong-willed woman, of which I'm guessing you're not (you had to ask this place for relationship advice?), you should run like the wind for two reasons:

First, if the male in question is truly an exhistentialist, he is misery wrapped in an enigma. There will never be any joy in Mudville, if you catch my drift.... I think a strong woman could deal with this, but she'd never truly be happy. An exhistentialist wouldn't care if she were, or not.

Second, if the male is just looking for a 'cool hook to get chicks' and is using the label, he's probably not worth your time. If you simply have to have this individual, expend the least amount of effort necessary. You'll thank yourself later.

In my own expereince, I was the first of the two. I say WAS. Until I went on a date with a woman I met in a library. We sat across the table from each other and I ran on and on, much like your intended male target must do, and she stared at me in wide-eyed admiration over the rim of her cup. At least that is what I thought was happening---until she finally gasped, choked on her drink, and laughed until it came out of her nose. When the dust settled, she was laying on the floor of the restaurant, with her feet on the chair, and two tiny pieces of tissue shoved delicately up her nostrils. She then proceeded to open fire on every one of my 'theories'.

I asked her to marry me, and in the theme of smart women, she said no, but the important thing was that it made a clear distinction in time, from being a man who WAS an exhistentialist, to being a man who read them. I suggest you look for the same in your proposed mate.